There are several choices in the packing and shipping industries for shock absorbing material for protecting products from damages due to shocks and vibrations during the distribution channels of the products. One of those choices has been styrofoam. Although using styrofoam as packaging material has benefits such as good thermal insulation and light weight, it also has various disadvantage. For example, recycling styrofoam is not possible, soot is produced when it burns, a flake or chip comes off when it is snagged because of its brittleness, and expensive mold is needed for its production, and a relatively large warehouse is necessary for storage.
Therefore, to solve such problems noted above, other packing materials and methods have been proposed. One method is a fluid container that seals in liquid or gas such as air (hereinafter “air-packing device”). Such an air-packing device has excellent characteristics that solve the problems involved with styrofoam. First, because the air-packing device is made only of thin plastic films, it does not need a large warehouse for storage until immediately prior to product packing when the air-packing device is inflated. Second, a large mold is not necessary for its production because of its simple structure. Third, the air-packing device does not produce a chip or dust which may have adverse effects on precision products. Furthermore, recyclable materials can be used for the films forming the air-packing device. Additionally, the air-packing device can be produced and stored with low cost and transported with low cost.
An example of a structure of such an air-packing device is shown in FIG. 1. The air-packing device 20 includes a plurality of air containers 22 and check valves 24, a guide passage 21, and an air input 25. The air from the air input 25 is supplied to the air containers 22 through the air passage 21 and the check valves 24. The air-packing device 20 is composed of two thermoplastic films that are bonded together at bonding areas 23a. Each air container 22 is provided with a check valve 24.
One of the purposes of having multiple air containers with corresponding check valves is to increase the reliability of the air-packing device. Because each air container 22 is independent from the others, even if one of the air containers suffer from an air leakage for some reason, the remaining air containers 22 that are still intact and remain inflated. Therefore, the air-packing device can still function as a shock absorber.
FIG. 2 is a plan view of the air-packing device 20 of FIG. 1 when it is not inflated showing bonding areas for closing two thermoplastic films. The thermoplastic films of the air-packing device 20 are bonded (heat-sealed) together at bonding areas 23a which are rectangular periphery thereof to air-tightly close the air-packing device. The thermoplastic films of the air-packing device 20 are also bonded together at bonding areas 23b each forming the boundary between two adjacent air containers 22 to air-tightly separate the air containers 22 from one another.
When using the air-packing device, each air container 22 is filled with air from the inlet port 25 through the guide passage 21 and the check valve 24. After filling the air-packing device with the air, the expansion of each air container 22 is maintained because each check-valve 24 prevents the reverse flow of the air. The check valve 24 is typically made of two small thermoplastic valve films that are bonded together to form an air pipe. The air pipe has a tip opening and a valve body to allow the air flowing in the forward direction through the air pipe from the tip opening but the valve body disallows the air to flow in the backward direction.
As noted above, the structure of the air-packing device having a multiplicity of air-containers, each of which having a check valve that prevents reverse flow of compressed air, is advantageous in improving reliability of the air-packing device. In order to allow various shapes (contour) of air-packing devices to accommodate various shapes and sizes of products to be protected, it is desirable that the check valve can be manufactured with ease and allows flexibility of designing the air-packing device.